While reading the comments to our review of Doxie's portable document scanner a few weeks back, I noticed that a few of you were eschewing scanners entirely in favor of these phone apps, so I decided to dig a little deeper. It turns out that there's no shortage of scanner software for both iOS and Android, and most of the apps are pretty similar in operation: take a picture of a document with the phone's camera, apply post-processing filters as desired, and then save the scans to your phone. The differences lie in price, and in what the apps can do with your "scans" after you've made them.

Cheap and simple: JotNot Scanner Pro

If you're using iOS and want something simple and inexpensive, MobiTech 3000's free JotNot Scanner will get the job done. You use the app by either snapping a photo of your document or importing it from your photo library, at which point it will attempt to detect the edges of your document. The app does a pretty good job of edge detection by itself, but you can move the edges of the document around before post-processing to make sure your scan just shows the document and not part of your desk or table underneath. For the best results, you'll want to get in as close to the document as you can, make sure that it's lying flat, and ensure that you're not taking the photo from an excessive angle—this can cause odd bending and warping of the final scan—it's especially problematic if you're trying to capture a sheet of paper that has begun to curl at the edges.

Most scanner apps do a decent job of straightening out crooked edges that will result from taking pictures with your phone.

By default, the app then ramps up the contrast to eliminate noise and more accurately simulate an actual scanned document. This does have the unfortunate side effect of eliminating detail, however—when you're shooting a black-and-white document in a well-lit room, most details come through well enough to be perfectly readable, but fine detail and color accuracy can be obliterated by this process, especially in low light. You can choose between a few scan enhancement presets (or define your own custom enhancement presets) in the app's settings to try to get more satisfactory results if you're having problems—the source photo of the scan is saved so that you can come back to it and try again as often as you need to.

Blurry pictures or pictures taken in low light are going to lose a lot of fine detail during post-processing.

Taking pictures in better lighting results in much more legible text.

Once you've scanned a document, you're free to add more pages to create a multi-page scan. To move your scans to your computer, the free version is capable of saving scans to your camera roll, which you can then move to your computer via Photo Stream or a USB cable. There's also a Pro version available for $1.99 that adds support for uploading to Evernote, Box.net, Dropbox, Google Docs, and WebDAV shares; e-mailing scans; and converting scans into JPG, PNG, and PDF; but you can save money by downloading the application and activating that functionality via a $0.99 in-app purchase.

JotNot can e-mail scans in one of several file formats.

The paid version of JotNot also supports uploading to several of the most popular cloud services.

Using JotNot's WiFi sharing feature, you can connect to your phone from your computer to download scans.

Other JotNot features of note include the ability to send faxes via an in-app purchase; the feature costs $0.99 for faxes up to five pages long. Using your phone's IP address, you can also use the app's WiFi sharing feature to connect to the device with your PC or Mac to download individual scans or a complete .zip archive of every scanned document stored on the device.

More costly, more capable: CamScanner+

CamScanner+ costs $4.99 and comes in both iOS and Android versions. Like JotNot, it can e-mail scans in PDF or JPG formats (but not PNG), save scans to your phone's photo library, and integrate with cloud services like Google Docs, Box.net, Dropbox, and Evernote. However, the higher price gets you some additional features.

CamScanner lets you tag scans, making them easier to organize and find later.

Writing descriptive notes can also help you find scans more easily later.

The app is better at storing and organizing scans, and allowing you to find them later: scans can be categorized under one of several predefined or custom-made tags, making it easier to keep your business cards separate from your receipts, and you can make notes on each scan that you can then search for later. CamScanner also includes optical character recognition (OCR), which can make the text of scanned documents searchable, useful if you're digging through your scans looking for one particular document.

The edge detection and enhancement process in CamScanner is very similar to JotNot.

The process of actually taking and/or importing pictures is very similar to JotNot, as you can see above, but CamScanner uses its own picture-taking UI instead of the native UI, giving it a couple of extra options. For one, the app can easily switch between single-page and multipage documents as you're taking the pictures with just a flip of a (virtual) switch, rather than having to take and process one picture at a time as you do in JotNot. This greatly expedites the process of creating a multipage document, though a document scanner with a sheet feeder will obviously be faster still.

The switch on the left allows you to switch quickly between single- and multi-page scans.

To my eye, CamScanner also labels its scan enhancement options more clearly—rather than burying them in a Presets menu, the different options are presented to you right after your phone finishes enhancing the scan, allowing you to make changes on the fly. Like JotNot, CamScanner keeps a copy of the original photo so you can go back and retouch your scans as needed.

Changing the way your scan looks is quicker in CamScanner, and you can see the changes in real time in the image preview.

Since scanned documents also contain some sensitive information, CamScanner gives you the option to set an app-specific passcode that is independent of your device's passcode—that way, even if you share the phone or tablet with family members or coworkers, they can't immediately access all of your scans.

A free version of CamScanner is also available for iOS and Android; while it can upload to cloud services and do much of what the paid version can do, it uses advertisements and puts a watermark on everything it scans—the latter is not especially desirable for professional usage. It also lacks the OCR capabilities of the paid version.

Neither JotNot Scanner nor CamScanner are feasible for high-volume use, for cases where detail is of the essence, or for excessively damaged documents that won't lie flat on their own. If all you need to do is scan a few business cards or receipts every now and again, though, scanner apps can do the job of a portable document scanner for a fraction of the price.

Promoted Comments

Missed the best one IMHO - FasterScan. The free version is very functional, and the paid for version (FasterScan+) gets you even more options. I've been using that app quite a bit for the last three weeks.

Your example screenshots are awful -- you must have your settings wrong. I use a couple of these apps frequently, and here is a typical example:

The text is wavy because it came from a book. The pic was taken in ordinary office light on an iPhone 4 (not the 4S with the better camera). The key setting is, for documents at least, to do black-and-white (i.e., two colors: black and white, not grayscale). The sample is a crop of a portion of a full page of text, with the original in a 12-point or so font.